999 resultados para Fermentation processes
Resumo:
Ethanol is the most suitable substitute for oil-based fuels. The performance of the fermentation is affected by several factors, therefore the aim of this work was to evaluate the efficiency of the fermentation of a hydrolyzed must of sweet potato using three strains of the Saccharomyces cerevisiae. It was also evaluated the effect of three forms of the processes conduction in the fermentation yield, efficiency and viability of yeast at the end process. Among the parameters evaluated, only the cell viability showed significant difference. The strain PE-2 would be the most suitable for the fermentation of the hydrolysed sweet potato.
Resumo:
CeO2 and mixed CeO2-ZrO2 nanopowders were synthesized and efficiently deposited onto cordierite substrates, with the evaluation of their morphologic and structural properties through XRD, SEM, and FTIR. The modified substrates were employed as outer heterogeneous catalysts for reducing the soot originated from the diesel and diesel/biodiesel blends incomplete combustion. Their activity was evaluated in a diesel stationary motor, and a comparative analysis of the soot emission was carried out through diffuse reflectance spectroscopy. The analyses have shown that the catalyst-impregnated cordierite samples are very efficient for soot oxidation, being capable of reducing the soot emission in more than 60%.
Resumo:
Six wines were distilled in two different distillation apparatus (alembic and column) producing 24 distillates (6 for each alembic fraction - head, heart and tail; 6 column distillates). The chemical composition of distillates from the same wine was determined using chromatographic techniques. Analytical data were subjected to Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allowing discrimination of four clusters according to chemical profiles. Both distillation processes influenced the sugarcane spirits chemical quality since two types of distillates with different quantitative chemical profiles were produced after the elimination of fermentation step influence.
Resumo:
The volatile fraction of sugar cane spirits plays a key role in the quality and acceptance of these beverages. The composition of this fraction is dependent on the way sugar cane collection, fermentation, distillation and aging are carried out. The materials used in these processes strongly influence chemical composition. Acetic acid, acetaldehyde, ethyl acetate, ethanol, 2.3-butanedione, n-propanol, 3-methyl-buthanol and isobuthanol were the major volatiles in spirits. Dimethyl sulfide and n-propanol impaired beverage flavor. Ethyl octanoate, 1.1-diethoxy-ethane, 2-phenylethanol and 3-methyl-butanol were important aroma contributors. Ageing allows the extraction of flavor-active components (e.g., phenolic compounds) from wood.
Resumo:
An investigation was conducted into the production of xylose by acid hydrolysis of rice husks and its subsequent bioconversion to xylitol. The parameters were optimised using the response surface methodology. The fermentation stage took place with the aid of the yeast species Candida guilliermondii and Candida tropicalis. An evaluation of the influence of several biomass pre-treatments was also performed. The effects of the acid concentration and hydrolysate pH on xylitol global yield were also assessed, and the highest yield of xylitol was 64.0% (w/w). The main products, xylose and xylitol, were identified and quantified by means of liquid chromatography.
Resumo:
This contribution discusses the state of the art and the challenges in producing biofuels, as well as the need to develop chemical conversion processes of CO2 in Brazil. Biofuels are sustainable alternatives to fossil fuels for providing energy, whilst minimizing the effects of CO2 emissions into the atmosphere. Ethanol from fermentation of simple sugars and biodiesel produced from oils and fats are the first-generation of biofuels available in the country. However, they are preferentially produced from edible feedstocks (sugar cane and vegetable oils), which limits the expansion of national production. In addition, environmental issues, as well as political and societal pressures, have promoted the development of 2nd and 3rd generation biofuels. These biofuels are based on lignocellulosic biomass from agricultural waste and wood processing, and on algae, respectively. Cellulosic ethanol, from fermentation of cellulose-derived sugars, and hydrocarbons in the range of liquid fuels (gasoline, jet, and diesel fuels) produced through thermochemical conversion processes are considered biofuels of the new generation. Nevertheless, the available 2nd and 3rd generation biofuels, and those under development, have to be subsidized for inclusion in the consumer market. Therefore, one of the greatest challenges in the biofuels area is their competitive large-scale production in relation to fossil fuels. Owing to this, fossil fuels, based on petroleum, coal and natural gas, will be around for many years to come. Thus, it is necessary to utilize the inevitable CO2 released by the combustion processes in a rational and economical way. Chemical transformation processes of CO2 into methanol, hydrocarbons and organic carbonates are attractive and relatively easy to implement in the short-to-medium terms. However, the low reactivity of CO2 and the thermodynamic limitations in terms of conversion and yield of products remain challenges to be overcome in the development of sustainable CO2 conversion processes.
Resumo:
Screening of biomass of a new marine-derived strain of Penicillium roqueforti, as produced by liquid-state fermentation, led to the identification of several volatile organic compounds active in the fatty acid pathway as well as fragments produced by their catabolism, terpenoids, and metabolites from the shikimic acid pathway. In addition, five non-volatile organic compounds, triolein, ergosterol peroxide, 9(11)-dehydroergosterol peroxide, 4-hydroxybenzaldehyde, and d-mannitol, were isolated and identified by spectroscopy. The results showed that this fungal strain did not produce any mycotoxin in the culture conditions applied, and thus is useful for industrial applications, where high value-added biomolecules are generated.
Resumo:
Biological production of hydrogen through anaerobic fermentation has received increasing attention and offers a great potential as an alternative process for clean fuel production in the future. Considering biological systems for H2 production, anaerobic fermentation stands out, primarily due to its higher production of H2 compared with other biological processes. In addition the possibility of using different agro-industrial wastes as substrates opens up infinite possibilities. The development and implementation of sustainable processes for converting renewable materials into different value-added products is essential for the full exploitation of Brazilian agro-industrial wastes.
Resumo:
This work is devoted to investigation of wave processes in new hybrid ferrite/ferroelectric structures. Spin wave devices based on ferrite films have disadvanteges. And their applications are limited. Investigated structures allow to overcome disadvantages. This investigation helps to create new class of devices. Electromagnetic analysis of hybrid spin-electromagnetic waves in ferrite/ferroelectric structures were done. As a result dispersion relation was found. Numerical solution of this dispersion relation gave us follow results. These structures can be effectively tuned by external electric and magnetic field. Methods to increase tuning range were suggested. It was found that such structures have one basic disadvantage which is connected with presence of thick ferroelectric layer. To solve this problem is to use thin ferroelectric films. But this decreases tuning range. It was confirmed by experiment that this structures can be effectively tuned by electric and magnetic fields. Resonance characteristics of ferrite/ferroelectric resonator were succesfully tuned by magnetic and electric field.
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IT outsourcing refers to the way companies focus on their core competencies and buy the supporting functions from other companies specialized in that area. Service is the total outcome of numerous of activities by employees and other resources to provide solutions to customers' problems. Outsourcing and service business have their unique characteristics. Service Level Agreements quantify the minimum acceptable service to the user. The service quality has to be objectively quantified so that its achievement or non-achievement of it can be monitored. Usually offshoring refers to the transferring of tasks to low-cost nations. Offshoring presents a lot of challenges that require special attention and they need to be assessed thoroughly. IT Infrastructure management refers to installation and basic usability assistance of operating systems, network and server tools and utilities. ITIL defines the industry best practices for organizing IT processes. This thesis did an analysis of server operations service and the customers’ perception of the quality of daily operations. The agreed workflows and processes should be followed better. Service providers’ processes are thoroughly defined but both the customer and the service provider might disobey them. Service provider should review the workflows regarding customer functions. Customer facing functions require persistent skill development, as they communicate the quality to the customer. Service provider needs to provide better organized communication and knowledge exchange methods between the specialists in different geographical locations.
Resumo:
As primary objective, this thesis examines Finnair Technical Procurement’s service quality with its underlying process. As an internal unit, Technical Procurement serves as a link between external suppliers and internal customers. It is argued that external service quality requires a certain quality level within an organization. At the same time, aircraft maintenance business is subject to economic restraints. Therefore, a methodology was developed with a modified House of Quality that assists management in analyzing and evaluating Technical Procurement’s service level and connected process steps. It could be shown that qualitative and quantitative objectives do not exclude each other per se.